HottLS1Z

iTrader: (5)

I have a TCI 4500 Stall converter that I am having lockup issues with ever since I had my trans re-built, how much power would this show loss of to the wheels on a dynojet? I have heard anywhere from 35-60 on a large loose converter like this anyone have more accurate #'s ? A local trans shop said average for unlocked loss on a dyno is about 1RWHP per 100RPM stall rating so in my case 45RWHP...

12secSS

iTrader: (30)

Anyone that gives you some formula for loss, or a set firgure is an idiot. The converter has many features that would alter the loss versus locked (stator, impeller, turbine design), also the setup of the vehicle has a huge impact on that variable. Some high quality converters lose about 10rwhp while other lower quality units will see up to 75rwhp. Only way to determine the loss is to do two tests unlocked and two tests locked on the dyno, with all paramter similar (ECT, Trans temp, etc...).

edcmat-l1

iTrader: (10)

^^^^I agree completely. Too many variables to make a blanket assumption.
TCIs are pretty nice converters. But, if it doesnt have a high hp clutch, you may wipe it out if you're making any kind of power, and you're trying to run it locked on the dyno.
Looking at your mods, you may have trouble locking it and keeping it locked on the dyno. I've seen em go both ways with similar type set ups.

HottLS1Z

iTrader: (5)

Well its a custom built converter compitetion grade with lockup, so I would imagine it has the good clutch, considering its an $800 converter...it wont lockup even under normal driving though, I think I have a bad TCC silinoid or something gotta have it checked out.

HottLS1Z

iTrader: (5)

Anyone have any exp with a large TCI locked up and unlocked on a dyno for an average?

edcmat-l1

iTrader: (10)

You can count on a good 25-30 hp loss. Could be more, but usually not less.

DeltaT

iTrader: (5)

Yep, unlocked my 383/Vortech was ~35rwhp less than locked, and ~20rwt. That was through a Hughes 2600 stall and 4L80E.

Jim

HottLS1Z

iTrader: (5)

And the larger/looser the converter the more loss there would be correct?

edcmat-l1

iTrader: (10)

For the most part, yes. But some are worse than others. WAY worse.

rdmelton

iTrader: (25)

I went to the dyno last weekend, and I did back to back pulls with everything else constant except for locking up the converter. I gained 3 horsepower by locking it, and the guy running the dyno said that the torque converter was likely slipping, so my results probably aren't particularly helpful to answer your question. Anyway, here is the full results if anyone is interested
http://rdmelton.autoeducation.com/cars/ws6/dyno.html

12secSS

iTrader: (30)

Based on your mod list, are you on a stock converter? If so, then 3rwhp difference is correct! Stock converter are very efficient units and it is not possible for an aftermarket unit to be mroe efficient then OEM. You numbers line up fine.

Here is a thread regarding locked versus unlocked graph of my car, this is a B&M unit (70442) I designed when I still worked there.

https://ls1tech.com/forums/automatic-transmission/828032-b-m-ls1-converter-efficiency-dyno-results.html

382ssz28

iTrader: (24)

I just got mine back from W2W with Rich's tune and gained 7HP locking the 4000 Vig.

gillbot

iTrader: (27)

Last I checked mine, it was only around 20RWHP loss on my Yank PT4000.

HottLS1Z

iTrader: (5)

Was talkin to a guy at work the other day who had his lockup clutch go out and put down 393 unlocked on his H/C/I 02 Z last yr on a dyno jet, put in a new convert with lockup and put down 438 locked. Old converter was a TCI 4400 new one was a Vig 4400 no difference at the trac though he said. He said this was all done in 1 week and weather conditions were very similiar.